Gretz is currently in his first season at Ohio State after a stellar prep career at Apple Valley High School (MN). As a true freshman, Gretz has appeared in 19 games (16 starts) for the Buckeyes and has posted a .200 batting average with two doubles and 9 RBIs. A four-year letter-winner at Apple Valley, Gretz was a two-time honorable mention All-State honoree and two-time team captain. As a senior he batted .322 with 19 RBIs, 13 runs scored, and a .459 on-base percentage. Prior to that season he was named to the 2011 Preseason High School All-Region Second Team by Perfect Game USA. Gretz also had the opportunity to be a part of two National Championship teams in summer ball with the Ohio Warhawks where he posted a .485 batting average with 12 doubles and 45 RBIs during the 2011 summer. The Ohio Warhawks are a top prep summer league team comprised of 18 and under players. Gretz has family ties to the game as his brother Nick played four years in the Colorado Rockies organization as well as a stint in independent ball for the Saint Paul Saints. He is a native of Apple Valley, Minnesota.